نتایج جستجو برای: ecotone
تعداد نتایج: 925 فیلتر نتایج به سال:
Ecotones are transition zones that form, in forests, where distinct forest types meet across a climatic gradient. In mountains, ecotones are compressed and act as potential harbingers of species shifts that accompany climate change. As the climate warms in New England, USA, high-elevation boreal forests are expected to recede upslope, with northern hardwood species moving up behind. Yet recent ...
A molecular maker for authenticating species origin of the stingless bee (Trigona collina) was developed. Initially, amplified fragment length polymorphism analysis was made of 11 stingless bee species using 64 primer combinations. A 316-bp band found only in T. collina was cloned and sequenced. A primer pair (CUTc1-F/R) was designed and tested for species-specificity in 15 stingless bee specie...
Biogeosciences Discussions This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. Abstract Atmospheric concentrations of reactive nitrogen species (Nr) from 2009 to 2011 are reported for ten sites in Xinjiang, an arid region in Northwest China. Concentrations of NH 3 , NO 2 , particulate ammonium and ...
The Iberian hare Lepus granatensis is a common and abundant species throughout the Iberian Peninsula; however, studies documenting its ecology are scarce. Between August 1996 and September 1997, after a long drought, we studied the effects of a widespread flood on the Iberian hare ecology in ecotone pastures of Doñana National Park. Hares were captured using vertical nets through part of 1996 a...
Considering that habitat use by amphibians is related both with climate and environmental features, we tested the hypothesis that anuran assemblages found in different phytophysiognomies and in different seasons vary in structure. Additionally, we searched for species which can be indicators of habitat and seasons. The study was conducted in the Pampa biome, southern Brazil. Sampling was done t...
In coming decades, global climate changes are expected to produce large shifts in vegetation distributions at unprecedented rates. These shifts are expected to be most rapid and extreme at ecotones, the boundaries between ecosystems, particularly those in semiarid landscapes. However, current models do not adequately provide for such rapid effects-particularly those caused by mortality-largely ...
Many fishes shelter in mangrove habitats by day and forage mostly in seagrass beds by night. This pattern of diel habitat use has been attributed to a predator avoidance strategy, whereby predation risk is reduced by alternating between the cover afforded by prop-roots during the day and darkness at night. We employed a series of diel tethering experiments in Biscayne Bay (Florida, USA) to empi...
ACKNOWLEDGEMENTS: This thesis is a product under the International Polar Year (IPY) core project PPS Arctic (http://ppsarctic.nina.no) which was financially supported by the Research Council of Norway via the IPY grant 176065/S30 to A. Hofgaard. I would like to thank my supervisors Lars Söderström (NTNU) and Annika Hofgaard (NINA) for their time and effort in helping me build and structure this...
Abstract Background Lake is a critical part of Tibet's hydrological cycle, the lake–terrestrial ecotone most sensitive area in water and terrestrial ecosystem. For ecological protection maintenance lakeside zone, defining upper boundary key issue that needs to be solved urgently. However, characteristics made it difficult delimit. Wetland herbs are characteristic plants ecotone, their distribut...
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